1. Field of the Invention
The present invention relates to an electric motor with a scatter preventing member which prevents scattering of component parts of a bearing to an inside of a housing.
2. Description of Related Art
In many electric motors, a drive shaft attached to a rotor is supported by bearings which are attached to an end part of a housing on an output side and an end part on an anti-output side. These bearings are fastened by being fit into circumferential grooves which are formed on an inner circumferential surface of the tubular housing. Normally, inner races of the bearings can be moved with respect to outer races within the range of the axial gaps, and therefore depths of the circumferential grooves should be substantially the same as the thicknesses of the outer races in the radial direction so that the inner races do not interfere with the lateral walls of the circumferential grooves. An electric motor with such bearing mounting structures is illustrated in JP-A-H08-51752, JP-A-H08-294247, and JP-A-H08-335367.
In recent years, there has been an increasing need for electric motors with a larger maximum output and maximum torque etc. and excellent compactness. However, if the drive shaft on the electric motor side is coupled by belt to the driven shaft on the load device side, the radial load on the drive shaft is increased as the maximum torque of the electric motor becomes greater. Further, an excessive radial load on the drive shaft may cause damage to or even early destruction of a bearing. If the operation of the electric motor is continued in this state, the bearing will be disassembled and therefore the shield plate, holder, rolling elements, and other bearing parts are liable to be scattered. If the bearing parts are scattered to the inside of the housing, there may be a serious secondary problem which involves damage to the structural parts inside of the housing such as the stator winding and rotor core.
An electric motor which can prevent structural parts inside of the housing from being damaged by the component parts of a bearing is being sought.